Ratchet hoist



Nov. 6, 1962 R. s. SELSET 3,062,505

RATCHET HOIST Filed July 20, 1961 INVENTOR. RON/9L0 5. SELSET' ATTO R N EYS 3,062,505 RATCI ET HOIST Ronald S. Selset, Seattle, Wash, assignorto Beebe Bros.

Seattle, Wash, a partnership Filed July 20, 1961, Ser. No. 126,806 Claims. (Cl. 254-167) This invention relates to an improved ratchet hoist of the type illustrated and described in pending application of Dan D. Beebe for Letters Patent of the United States filed April 25, 1960, Ser. No. 24,466, and namely a ratchet hoist providing a winding drum having a ratchet wheel on one end thereof and employing with said ratchet wheel two pawls, one a feed pawl pivotally carried by a yoke swingable by hand in reciprocal motion about the center of the winding drum as an axis, and the other a holding pawl pivotally carried by a frame in which the winding drum is journaled. The said ratchet hoist employs two springs, one a single duty and the other a double duty spring. in the operation of winding cable upon the drum the single-duty spring urges the feed pawl into engagement with the ratchet wheel while the double-duty spring urges the holding pawl into engagement with the wheel so that the latter will alternately ratchet and catch relative to the teeth of the wheel while the yoke is swung, respectively, in its forward and return directions of swing motion, the feed pawl perforce catching and ratcheting in the respective instance. The operation of unwinding cable from the drum is obtained by dropping off single teeth in each of a succession of short reciprocations of the yoke. To accomplish this action the single-duty spring is made inactive to the feed pawl, while the double-duty spring acts upon both pawls. In this said action, and as a consequence of the fact that there is an intermittent engagement and disengagement as between the feed pawl and the double-duty spring, a rubbing action takes place between the two. The spring wire of which the double-duty spring is composed has been heretofore subject to considerable wear. The life span has not been unduly long and the springs must be continually inspected to insure replacement before breakage can occur. Considerable hazard is present should breakage take place while the hoist is in service.

For its principal object the present invention aims to provide a ratchet hoist of the above nature in which the presently used double-duty spring is replaced by a wire spring of perfected design and one, especially, which is subject to such negligible wear that the life of the spring exceeds the normal life of the hoist.

The invention has the further object of designing a wire spring, to perform such double duty, which will continue to perform its single duty of maintaining the holding pawl in functioning condition even in the unlikely event that breakage should occur in the branch of the spring which is subject to rub from the feed pawl.

The above and other objects and advantages in view will appear and be understood in the course of the following description and claims, the invention consisting in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawing:

FIGURE 1 is a fragmentary longitudinal vertical sectional view illustrating a ratchet hoist constructed to embody preferred teachings of the present invention.

FIG. 2 is a fragmentary transverse vertical sectional view thereof on line 22 of FIG. 1.

FIG. 3 is a side elevational view of the spring employed in the present invention; and

FIG. 4 is a top plan view of said spring.

The disclosure of the above-identified patent application is relied upon to fully illustrate and describe the character of ratchet hoist to which the present invention pertains.

3,062,565 Patented Nov. 6, 1962 ice Employing similar reference characters to designate corresponding parts, the numeral 17 represents one of two checks of a cast cheek-frame. A winding drum occupies the opening between the cheeks of said frame and is fixed to a cross-shaft 18 having its ends journaled for r0- tation in said cheeks. The winding surface 19 of the drum has an integral ratchet wheel 21 at one end thereof. The wire spring, designated generally by 60, to which the improvements of the present invention are directed works in a space which is provided between the ratchet wheel and the adjacent cheek.

A yoke 22 straddles the cheek-frame with its two arms pivoted to protruding ends of the cross-shaft, and beyond the edge limits of the cheek-frames a shaft 32 extends between the yoke arms. A feed pawl 33 is freely pivoted on this shaft 32 but is held against endwise travel, being positioned so as to occupy the substantial plane of the ratchet wheel so that a dogging end 34 of the pawl engages the teeth of the ratchet wheel. The pawl can be biased either into or out of engagement with the ratchet wheel by means of a manually controlled spring 37 flipped against either of two horns 35 or 36, selectively. The dogging end of the pawl has an car 41 jutting laterally therefrom into the space hereinbefore referred to which is occupied by the spring 60. This car has an arcuate bottom profile when viewed from the side, and this arcuate bottom edge is made concave in cross-section to provide a groove 49.

Below the winding drum a cross-shaft 42 extends parallel to the main shaft 18 in approximately the same vertical plane which is occupied by such main shaft. A holding pawl 43 for the ratchet wheel is pivoted intermediate its ends to the shaft, the pawl being properly positioned by a snap-ring 44. One arm 45 of the pawl provides a buttress tip, and the wire spring 60 urges this tip into dogging engagement with the ratchet wheel. The other arm 47 of such holding pawl limits the retraction travel of the dogging tip by being brought to bear against a stud 5t) rooted in the proximal check of the frame. The dogging tip is retracted either manually by lifting said arm 47 or by the act of bringing the ear 41 of the feed pawl downwardly against the spring 60, which will be now described.

The wire composing said spring is provided with a multiple-turn loop 61 which, in the application of the spring to the ratchet hoist, slips over said stud 56. A short branch 62 of the spring lies uppermost and extends inwardly from the loop in the substantial plane of the groove 49 so as to be lodged in the latter by the act of bringing the feed pawl 33 downwardly. A considerably longer branch of the spring extends from the lower side of the loop parallel, or approximately parallel, to the branch 62 and is itself looped intermediate the ends. This latter loop, designated by 63, is brought upwardly and thence downwardly through an approximate 225 turn about a center paralleling the center of the loop 61 and produces a free section 64 which crosses the root section 65. The extremity 66 of the free section 64 is bent inwardly parallel to the axes of the loops and is caught in a side socket of the holding pawl. In order for said extremity to be caught in the side pocket it is necessary to force said free section outwardly in relation to the root section 65, responsively tensioning the free section so that the dogging end of the holding pawl is yieldingly urged radially inwardly into ratcheting engagement with the ratchet wheel. Depression of the short branch 62 acts counter to said spring thrust to move the dogging end of said pawl radially outwardly.

The functioning relationship between the two pawls is as follows:

Upon reciprocally moving the yoke in a counterclockwise direction, considered from the vantage point of FIG.

1, the feed pawl lodges behind a tooth of the ratchet wheel and causes the drum to responsively turn in a cable-winding direction, the holding pawl 43 simply ratcheting over successive teeth as spring 68 performs its normal function of biasing the dogging arm 45 against the wheel. In the clock-wise return motion the holding pawl lodges against a tooth of the wheel while the feed pawl ratchets over the then stationary teeth. Should it be desired to let out the cable while under load the action is performed by short-stroke reciprocal motion of the yoke at the low end of its permitted travel. Backing off one tooth at a time, the ear 41 of the feed pawl in this case acts during the counter-clockwise stroke to press downwardly against the short branch 62 of spring 68. This responsively retracts the dogging end 45 of pawl 43 from the ratchet wheel and as the yoke is then swung backwardly (clock wise) a distance of one tooth or more the ratchet wheel responsively backs off in unison a single tooth before the ear releases the spring 60 and permits the latter to again perform its normal function of pressing the holding pawl against the ratchet wheel.

The invention and the manner of its operation should be clear from the foregoing. Minor changes in the details of constructoin can be resorted to without departing from the spirit of the invention, wherefor it is my intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

What I claim is:

1. In combination with the'cheek-frame, winding drum, ratchet wheel, yoke, feed pawl, and holding pawl of a ratchet hoist of the character described in which the winding drum and the ratchet wheel turn in unison and are journaled for rotation between the cheeks of the frame, the yoke is journaled for reciprocating forward and return swing motion about an axis coinciding with the rotary axis of the drum, the feed pawl is carried for pivotal motion by a shaft extending between the arms of the yoke and is biased into ratcheting engagement with the ratchet wheel, and the holding pawl is carried for pivotal motion into and out of ratcheting engagement with the ratchet wheel by a shaft extending transversely between the cheeks of the frame below the drum: a wire sear spring pivoted to a pin which is carried by the frame to occupy a position spaced above the last-named shaft in the path travelled by the feed pawl and acting normally to yieldingly press the holding .pawl into ratcheting engagement with the ratchet wheel and serving additionally to retract the holding pawl out of said ratcheting engagement and at the same time yieldingly press the feed pawl into ratcheting engagement with the ratchet wheel for the working interval necessary to back off said ratchet wheel a single tooth as the yoke initially swings in its return stroke of reciprocation, the wire of which said spring is composed being formed within its length with a multipleloop coil which slips over the frame-carried pin and divides said spring wire into long and short branches both extending inwardly from the coil in a direction which is generally radial to the drum and with the short branch lying uppermost in a position to be engaged directly by the feed pawl as the latter nears the end limit of its forward travel, the long branch being formed with a loop intermediate its ends developed on an axis paralleling that of the coil to divide the long branch into a root section and a free section of which the latter extends downwardly from the loop at an angle of approximately 45 from the root section, interengaging means being provided by the free section of the spring at its extreme outer end and by the dogging end of the holding pawl for detachably connecting said extreme outer end to said dogging end, the element of said interengaging means which is provided by the holding pawl being so located upon the pawl that the connection of the spring with the holding pawl can be made only by expanding said angle to tension the loop of the spring.

2. Structure as recited in claim '1 in which the extremity of the springs free section is bent at substantial right angles to the parent section and lodges in a mating side pocket of the holding pawl to provide said attachment between the spring and the holding pawl.

3. Structure as recited in claim 1 in which the direct engagement between the spring and the feed pawl is provided by an car which juts laterally from the pawl and has an arcuate bottom profile when viewed from the side and which is made concave in cross-section to provide a groove in which said short branch of the spring seats.

4. The structure recited in claim 1 characterized in that the bend which produces the loop within said long branch of the spring has an approximate 225 development causing the free section to cross the root section.

5. in combination with a frame, a ratchet wheel carried for rotation by the frame, a lever carried by the frame for forward and return swing motion about an axis coinciding with the'rotary axis of the wheel, a feed pawl for the ratchet wheel carried for pivotal motion by the lever, and a holding pawl carried by the frame for pivotal motion into and out of ratcheting engagement with the ratchet wheel in a position spaced a moderate distance beyond a predetermined end limit to which the feed pawl travels in its forward swing motion: a wire sear spring pivoted to a frame-carried pin for rocker motion about an axis which parallels the rotary axis of the Wheel and lies be tween the holding pawl and said predetermined end limit of the feed pawls travel so that the spring occupies a position in the path travelled by the feed pawl and acts normally to yieldingly press the holding pawl into ratcheting engagement with the ratchet wheel while serving additionally to retract the holding pawl out of said ratcheting engagement and at the same time yieldingly press the feed pawl into ratcheting engagement with the ratchet wheel for the working interval necessary to back off said ratchet wheel a single tooth as the lever initially swings in its return stroke of reciprocation, the wire of which said spring is composed being formed within its length with a coil which slips over the frame-carried pin and divides said spring wire into long and short branches both extending inwardly from the coil in a direction which is generally radial to the wheel and with the long branch lying proximal and the short branch lying distal to the holding pawl placing the short branch in a position to be engaged directly by the feed pawl as the latter nears the end limit of its forward travel, the long branch being formed with a bend intermediate its ends developed on an axis paralleling that of the coil to divide the long branch into a root section and a free section of which the latter extends toward the holding pawl in acute angular relation to the root section, interengaging means being provided by the free section of the spring at its extreme outer end and by the dogging end of the holding pawl for detachably connecting said extreme outer end to said dogging end, the element of said interengaging means which is provided by the holding pawl being so located upon the pawl that the connection of the spring with the holding pawl can be made only by expanding said acute angle to tension said bend of the spring.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,724 Coffing Aug. 4, 1953 2,738,954 Du Bois Mar. 20, 1956 2,854,852 Clark Oct. 7, 1958 2,890,857 Hoffman June 16, 1959 2,913,224 Uhlig Nov. 17, 1959 2,927,771 Clark Mar. 8, 1960 

